Aquaponics - Easy automatic duckweed feeder

Sorry folks, just a quick proof of ID.

Hi BYAP.

Actually I do have something to post though.

I had another idea for an automatic duckweed dispenser, and it works!

The previous one looked like this...

Or this from the side...

In this new easy one, all you need to do is pump some water into a pond a that's a bit higher than your fish tank, then create a flat spillway that falls into your fish tank. Make the spillway quite broad so the outflow is slow (or have a low flow to the duckweed growing tank). The idea is to not have the duckweed all flow out. A good way to do this is to create some texture on the flat spillway. paint on some silicon mixed with some fine gravel or something. 

It's a good idea to add water to the duckweed pond so that the water swirls. This way the duckweed builds up in the middle, and less will flow out at each time it triggers.

If the flow and texture is correct, the duckweed wont flow over because it gets a bit stuck on the spillway. 

After a while, the duckweed grows thick enough that it blocks some of the water. In my little decorative system, I get a rise in tide of around six or seven millimeters before the pressure builds up enough and dumps about ten percent of the duckweed into the fish tank. 

It wont dump again until the duckweed has grown back.

The result of this is that you never run out of duckweed, you feed more duckweed in the summer (when duckweed is growing faster, and your fish want more food) and it's automatic.

Not a lot of posts for ages. but I'm still doing stuff. 

Aquaponics - Seed raising in sphagnum moss

Anyone looking for a nice clean medium to sprout seeds for aquaponics should have a look at sphagnum moss. The seedlings come out with out any damage to roots, and perfectly clean.

You can even place a wad directly into your system and put the seeds into it. Then either leave the moss in place for ever (it doesn't rot, but springs back into life, even though you buy it dry and dead).

You could also just pick it out once the plant had become established.

Here are radishes, and some kind of leek or something growing on my kitchen window sill.




120 Things in 20 years grew something!

Aquaponics - Float Valve Mod

I installed a float valve on my aquaponics system because I grow a huge sphere of slime in there as free food for my Golden Comets.

I'm currently making a half hearted attempt at breeding them.

My Float valve looks exactly like this pictured to the left.



I bought it on eBay for two dollars I think.

It works pretty well but it doesn't put out a lot of water. I'm guessing it was designed to keep a dog bowl full or something, and for this it would be perfect. But I need a little extra flow.

Here it is in it's full "on" position.




And here in it's "off" position.

It does "off" pretty well, although I'm not overly fussed about it's "off" state. I dont really care if it leaks a little.

As you can see from the black pipe leading into it, there are some holes to make a spray to add a little aeration, but also to make sure there is never a situation where there is zero flow.



I only have a dozen or so adult goldfish in my system, and it is capable of holding a lot more.

 It could cope without any flow for a day or two, but the fish seem to enjoy their water moving around a bit.

The problem is that the slimeball I'm cultivating in the tank can sometimes find it's way into the outlet. The result is an overflow, and the sump tank running dry. The pump hates it when that happens, and I was lucky enough to catch it just before it ran dry a couple of days ago.

The point of the float valve was to slow the amount of water entering the fishtank if the water level gets too high. But because the flow through the device isn't very high, it isnt quite doing the task I assigned it.

I decided to make it flow a little faster.

To this end, I taped out the pin that holds it all together with a chopstick.

As expected, everything fell apart nicely, and I found that the thing worked by the float levering a small slide with a silicone stopper on the end. This blocked the water outlet when the float was
... floating

The bottom bit has the float on the end and fits into the box section on the next bit up. The lowest bit of green slimy plastic is the silicone stopper that presses against the next higher up bit of green slimy plastic.


I should write operating manuals.

The inlet hole did indeed turn out to be pretty small. Perhaps this is so the silicone stopper has a nice large surface area to stop leaks.

But I dont care about leaks because even when the slime blocks my system, it always lets some water through.

It never blocks it perfectly.

So I drilled it out to a size that should let more water through, but still allow the float to shut down the flow.

I had to do it by hand because the chuck on my drill has decided that it likes having the 13mm drill in it and refuses to surrender it no matter how I try to persuade the thing otherwise.

Thats what you get for running water all over the chuck when drilling stainless hinges and trying not to overheat the drill bit.

Somewhat surprisingly, the thing all fell back together as easily as it fell apart.

A few taps of the pin and it was all good.









So now the flow looks like this when it's in the "off" position.

Not a bad result.

Most of that flow is because I didnt bother to clean up the hole I drilled.

"Drilled" is probably a bit of a fantasy really.

Lets just say I made a hole with a drill bit.

In the "on" position I get a lot more flow now.

All in all I think this can be called a complete success.

And perhaps more importantly, it  shows that maybe I can still do stuff.

It's been a while.




If I care enough, I'll clean up the hole and make it so the flow actually stops when the float is floating.

Trying to drill by hand is fine until you actually make it through the thing your drilling. Then it becomes very difficult to make a clean hole because the drill bit just tries to screw itself into the item.

This is the "before" shot.






And this is the "after" shot.

The result is you get three quarters of a hole as you brake through the plastic.

I'll file it back to something like round if it turns out to matter.





So...

I did something.


120ThingsIn20Years Some of the photos were even in focus!

Aquaponics - Vivipary strawberry propagation fail

It looks like my absurd strawberry has pretty much failed to do much of anything except go all floopy, and look a lot more like earth than it did a few days ago..

I was (of course) hoping it would change the world in some enormous way, but alas it was not to be.

On the up side, a few of my very healthy normal strawberry plants are actually doing quite well, and have started to send out yet more runners, so "normal" might turn out to be a pretty good approach after all.

I think This might be my first post without a photo, so given the strawberry has turned to what looks like earth, I'll post this pic in place of anything meaningful.



120 Things In 20 Years thinks  the world might have slipped back into normal mode when it comes to strawberry propagation.

Aquaponics - Strawberry propagation

I found a new way to propagate strawberries. Or at least it's new to me. The secret is to have the seeds sprout while it's still on the fruit.

Although I would have liked to leave it alone to see if they would all grow by themselves, the fruit is almost rotten so I thought it would be better to pick it and plant them all.

It came from a dirt garden so there was a lot of risk of it being eaten by things before they had a chance to grow.

I planted it into my aquaponics system.





From what I could see, all the seeds had sprouted.

I have no idea what conditions were required to make it happen or if they will actually end up growing, but the original plant was a modern lab created thing that didn't produce runners. Or almost didn't. From around 60 plants I think I've seen two runners in two years.

120ThingsIn20Years thinks the world is odd.

Aquaponics - Recycled Leeks

It turns out it's possible to recycle leeks.

Which is nice.

When you buy or harvest a leek, cut the base off like you might normally do, but perhaps be a little more generous in what you leave. ie cut the bottom off so that it's 1cm thick or so.

Also leave the roots on if they are there still.

Then just stick it into your growbed media and wait patiently for a bit.

If you bought your Leek from a supermarket and the roots are all removed, it takes quite a while before you see new growth. Like all things without roots, they try to grow enough of a root system to keep from getting all thirsty and dead as a priority, then start to put up the all the photosynthesising bits to get on with the business of growing in earnest.

But, if you leave the roots on when you harvest, or better yet, just cut the stem off and leave the roots in the media, you should see new stem growth right from the start.

Pictured here are three store bought Leek bases in different stages of growth.

All of these had no roots at all.

The one I pulled up was just harassed in order to have it's photo taken, but will no doubt be fine because the expanded clay media is very forgiving when doing such things as pulling up a plant just to take a photo of it's roots.

As far as I can tell it's growing normally, and should be a perfectly good Leek in no time.

There's always the chance that something strange might happen and it might turn to a piece of wood or something, but if it does, rest assured I'll probably get around to telling you before you waste too much of your own time doing this.



120ThingsIn20Years thinks it will probably work just fine.

Aquaponics - Selective yabby breeding

I still have my yabby brood in a small aquarium sitting on my desk. As I type I'm watching them going all crazy for some fish food flakes.

Some are much, much bigger than others. Originally the difference was only 10% or so, but now some are three times the size or more than the smallest.

I get the feeling that people would always selectively breed from the fastest growing yabbies so that they might get a more productive farm over a few generations, but studying their behaviour up close like I am, I'm starting to wonder if that might be a bad idea.

The big ones are always the aggressive ones.

No doubt they got that way because they are getting more than their fair share of the food supply, and perhaps by eating one or two of their brothers and sisters along the way.

Perhaps that's not a good way to run a farm. Where some of your cows are eating the others, or at least stealing all their food.

One of my batch of yabbies seems to not be part of any of this. It's on the large side of medium in size, and seems to spend most of it's time grazing algae from the surface of a sheet of gutter guard (plastic mesh to keep leaves out of your house gutters). Mostly it's left alone, and more often than not leaves others alone when they occasionally venture onto it's bit of turf.

I think this kind of beast might be a better candidate to breed from.

Not quite as big, but a lot more sociable and a bit less cannibalism.

And who knows, perhaps without the aggressive ones, this type would be just as big.

I'm going to try to find out.



120 Things in 20 years went to a lousy seafood restaurant, but now wants to eat more crustaceans.

Aquaponics - Yabby stocking density

I've been thinking about stocking density, and it isn't even close to the holiday season.

I've had a clutch of baby yabbies (freshwater crayfish like things) drop from their mother, and for the last week or two I've been watching their behaviour through the glass of their small aquarium.

They spend most of their time running the boundary and bumping into each other for a quick fight, then moving on.

The result of all this watching is that I've had an idea.

The popular numbers I hear for yabby stocking density are that you need one square metre of lake per adult yabby if you want to farm them to eat (and have them grow to a decent size), but I think that might not necessarily be the case. I think that perhaps you need a linear distance of boundary per yabby rather than an area.

I have a feeling that in a lake, the yabbies might also run the boundary, bump into each other, and fight for a bit before moving on. This would mean that a large normal shaped lake might hold less yabbies than a long thin lake that took up the same area. I'm trying to stop them fighting and to give them the illusion of having a decent patch of lake to call their own, so maybe, the longer the boundary, the more yabbies you can keep.

Maybe.

If this turns out to be true, a long thin lake with a series of baffles might prove to be the better bet.

Or not.

Who knows.








If it works I hope it makes a stack of yabby farmers a stack of money, or helps someone who depends on their yabby farm to eat eat a bit more, or perhaps it could help someone like me to grow some yabbies in their aquaponics system.

Who knows.



120 things in 20 years doesn't know.

Aquaponics - Yabbies!

I just raised some baby yabbies. Yabbies are a freshwater crayfish that call Australia home.

Which is nice.

So now I have to farm them.

Tricky.

Yabbies are so delicious that they tend to eat each other.

Yum!

Tricky.

The problem is they they each want a stack of space to call their own.

They also take their time growing, but I just found this from...

http://www.fish.wa.gov.au/Documents/aquaculture_yabbies/how_to_grow_bigger_yabbies.pdf

"Separating males and females by hand is time-consuming and prone to mistakes. To make this
easier and more accurate, a hybrid has been discovered that only produces male progeny (by
crossing male WA yabbies Cherax albidus with female Cherax rotundus yabbies from NSW)"

According to the Western Australian Government fishy people, "Monosex culture provides a 70 per cent increase in gross return to the farmer."

I've had my first batch of yabbies drop from their mother, so I'm now a little obsessed with high stocking rates. I have the entire clutch in a very small 30 litre tank. So far they don't seem to be hurting each other, but they are very vulnerable when they shed their crunchy outer shell to make room for the next bit of growing they plan on doing. Shedding your armour also turns your pincers into mushy things that are no good for pincing.

No good at all.

I put the berried (that's what we yabby farmers call yabbies with eggs stuck to their undersides) female in a cage made of gutter guard (a plastic mesh to keep leaves out of your house's gutters) so the delicious babies would fall through and wouldn't get eaten by their mum. It seemed to work. Babies would let go, spend a minute or so near their mother, then drop to the bottom and never return.

For high density raising, I have a bit of a moral problem with battery hen style conditions even though (or perhaps because) I did some work on a design a few years back. But now I have an idea that I think might work for an IBC.

Basically its a 3D zig-zag of shade cloth that works it's way down a container like a staircase...kind of, so that there is a minimum of 5cm and a maximum of 8cm between each level. I'll attach a stack of PVC homes on each level that get larger and fewer as they get to the top. All of them should point downhill a bit so food and waste don't get stuck, and the basic plan is that the bigger you are, the higher you rise in the yabby high-rise (with me being at the very top). There would be gaps around the edges, so the smaller yabbies and babies would be able to find their way down with ease. They can sort it out among themselves as to who gets the housing at the top nearest the biggest food.

Watching my adult yabbies, I see that when they eat they let a lot drop. They leave a lot of crumbs. They make Cookie Monster look like something best described with words like "refined". They are also bottom feeders, and are not opposed to eating a meal that has already made its way through somebody else's digestive tract. Or more than one somebody's digestive tract.

So my hope is that I can add fish feed, or even veggie scraps (yabbies aren't fussy) into the top, and draw nutrient rich waste water that has been munched into very fine particles from the bottom to add to my growbed.


120 Things in 20 years needs to learn stuff. It's been a while.

Aquaponics - Silver Perch

I just spent a very pleasant 45 mins watching (and patting) my silver perch eat duckweed. 

I took some video but ran out of arms to do everything (lighting, camera, patting) so tomorrow I'll get someone to help and get some decent footage.

I know this doesn't really qualify as worthy of you taking the time to read it, but I was pretty excited, so have to bang on about it to someone. And Mrs 120 Things in 20 years is already asleep. 

Wasabii - cold house

I've been thinking of growing some Wasabii and have been following a thread on Backyard Aquaponics discussing things like the temperature it likes.

It seems it likes to grow in less than 10c water, and less than 25c air.

I'm about to get two solar panels for my epic solar boat adventure, so when they're are not powering the boat, I'll be using them to power my aquaponics system, and I've been thinking of ways to keep the system cool to extend the trout growing season, so perhaps I could use them for that as well.

I ran the problem through the invention engine, and it suggested running coils of hose through a container of water in a fridge as a heat exchange. And connecting the hose to my system. This would obviously cost a lot to run because each time the water went through the growbed, it would collect a stack of heat on a hot day.

But if I put a shade house over the top, I might be able to work something out.

Wasabii likes shade as well, so it should be easy enough to get a couple of layers of that grown up bubble wrap they use for pool covers, and make a tent. Wasabii doesn't grow very tall, so it should only need to be around half a metre high. Perhaps on hinges so it can be lifted when access is required.

I'd add a window so I wouldn't need to let all the heat in whenever I took a peek.



120 Things in 20 years is being told to finish the boat first.

Aquaponics - Direct composter success

I just got back from my trip to the East coast of Australia, and was happy to find the system ticking along nicely.

Some of the dried duckweed in my direct composter looks like it might be trying to live again, but I cant tell if it's greening due to life or mould.

There must have been some heavy rain while I was away, as it was soaked through.

I think I'd better put a lid on it.

When I lifted it up I saw a stack of worms going to ground into the growbed, and some more hanging from the little composter.

The worms seem to like it.

It was also very easy to grab a handful of worms for the fish, so the fish seems to like it as well.

It should also be adding some nutrient back into the system, and also saving some because of the duckweed I removed, so the plant will like it as well.


All in all, I count this a complete success, and it seems like quite a good solution to my problem of only having one fish.



120 Things in 20 years thinks flying around in helicopters is a pretty good way to spend some time.

Aquaponics - Duckweed - direct composter

Having dried some duckweed by spreading it out on some concrete for a few days, the next stage in creating my direct composter is using my cheese press to bring it all together. My PVC cheese press has seen a few different purposes in it's lifetime, but this one looks like it might be the one it retires to.

The duckweed shrunk down to a quarter of it's former live self.

I found my PVC pipe with holes that was formerly a cheese press, and rinsed it thoroughly.

I filled it with the dry duckweed, and planted it into the growbed.











The day after tomorrow, I'm off on an adventure to the other side of the continent, but tomorrow, which is really the day after tomorrow a far as this experiment goes, I'll check to see if the worms like their new feeder. But really I'll be somewhere else.




120 Things in 20 years is wondering if anyone is actually following this convoluted narrative.







120 Things in 20 years thinks that as far as it can tell, it's made a worm motel.

Aquaponics - Direct composter - duckweed drying

My system has only one fish, and I'm getting a little worried about my growbed's worm population. I'm not confident there's enough fish waste going into the system to feed them all.

What I thought I might try is creating a small compost bin directly in my growbed to make sure the worms have enough to eat.

I have a lot of duckweed growing in my system, and that one fish has to power the new bigger growbed, and the duckweed.

Duckweed uses quite a bit of useful nutrient so I thought I should remove some, and add it back into the system via the composter.

 I pulled out a quarter of a bucket or so of my duckweed from the system, and dumped it on some dry, sheltered concrete to dry.










I need to dry it first to kill it, because the direct composter will be a small container full of holes, sitting directly in my growbed. That means it will be damp, and the duckweed might just stay alive.

As I understand it, worms feed on the stuff that feeds on rotting vegetation so live duckweed wouldn't work so well.


120 Things in 20 years seems to be growing plants for feed to grow other plants. I think I finally developed a way to make growing vegetables as inefficient as growing beef.

Aquaponics - New system at two months

In a couple of days my new system will be two months old.

I wasn't sure how it would go being on the wrong side of the house and in shade for all but a couple of hours a day, but it looks like it might be ok.

This is the original empty growbed two months ago.

And now it looks like this.

The lettuce in the foreground went in as store bought seedlings, and the rest was from seed, but I wasted a lot of time before I actually sowed them.

We have started harvesting leaves from the lettuce and within a week or two we should be picking rocket as well.





The growbed is around two metres long and a little over a metre wide, so it should keep us in salad greens with ease.

I've also planted a few sugar snap peas at the back because I like to eat them when I'm doing anything with the garden. There's not enough to harvest but I enjoy picking something and eating it at the growbed.

Also at the back I've planted quite a bit of basil, some coriander (cilantro), and a few other herbs.

That's all. Just a quick update.

Aquaponics - Venturi adjustment

I thought I'd make a little adjustment to my venturi as suggested by Mike Creuzer in a comment on this post on my Venturi air thing.

He thought I should have some extra bubbles breaking the surface, and it turns out it's a bit of a hot topic in great debate all over the place, but I noticed a very slight oil slick on the surface of the water. I guess lots of things case very slight oil slicks. Eucalyptus leaves for one. Uneaten fish food probably would. I suspect an oil slick - and I'm talking an almost invisible one - would have some effect on gaseous exchange between the atmosphere, and my fish tank's water.

I have no idea if that's true, but I figure it couldn't hurt to stir the surface a little.

So I trimmed the pipe carrying water and bubbles down to the bottom by an inch or so and now lots more bubbles exit.

A 1/4 second exposure shows how much extra water movement on the surface is actually going on.










After only a few seconds there was no more sign of the oil slick.

Aquaponics - Silver perch feast

I cant remember if I even mentioned this because I was probably in some kind of deranged pain killer broken rib induced state when it happened, but I may have forgotten to mention I ate one of my big silver perch.

It looked like this.

The South Australian Fisheries people suggest the most humane way (and best way to protect it's eating qualities) to dispatch a fish is to plunge it into an ice water slurry, and leave it there.

A few hours later I scaled and cleaned it, and lightly salted it inside and out.




I wrapped it in whatever you call thin plastic kitchen wrap where you live, and left it in the fridge for twelve hours, then cooked it whole.

It was one of the nicest fish I have ever eaten.

Crazy fat.

You cant really tell from this angle, but it was in very fat condition. Looking down from the top, it had that thick section just before it's tail like a dolphin.

Most wild caught fish don't seem to have that.

I'm guessing it's because life is a little tougher in the wild when you don't have an unlimited amount of feed available.

Anyway...

This fish was in very good condition and had excellent fat content.

Apparently silver perch fat is high in Omega 3, but it was mostly delicious.

It weighed 1.08kg gutted and scaled and was 33 cm long.

I wish I had built a much bigger system ages ago so I could have a lot more.

Successfully farming your own protein in only a couple of cubic meters or space is an amazing thing to be able to do in suburbia.

I totally recommend it.



120 Things in 20 years totally recommends it.

Aquaponics - Aeration

I'm planning on buying some trout in the next few days to grow in my aquaponics system, so I'm thinking a bit about my oxygen levels.

Toward the end of the trout growing period you have a lot of stuff acting against your trout. Your trout are big and make a lot of waste which depletes oxygen as it breaks down, your trout are big and need lots of oxygen, and your weather is getting warmer,  and warmer water doesn't hold as much gas as colder weather does.

You can test this by opening a warm can of beer, or waiting a few years and watching what happens when the oceans stop absorbing carbon dioxide as they warm up a bit.

Anyway...

I have a tube dumping water from my growbed to my sump.

This much water.

It's not under pressure, but is simply overflowing from the growbed at that height. ie this tube's height regulates the depth of the growbed.

no pressure

The tube stopped a few inches above the water and made some nice splashing and bubbling which I thought was adding some oxygen.

I'm probably quite correct in thinking that.

But then I added a tube all the way to the bottom of the tank, and pricked a few holes in the tube just after a narrowing where there was an elbow.

This sucks air into the tube via the Venturi effect.








Apparently, this is because the water experiences higher pressure at the restriction just below the elbow, but then lower pressure when the tube becomes wider again. The result of the low pressure is that it sucks in air.

Which is a little odd.

When you put holes in (or before) the bit that's actually restricted, the holes blow out water.

I know because I checked.

So the result is that oddly enough, air is drawn in and the flow of the water draws it down.

Even more oddly, is that the bubbles don't ever really come out. Some do when the water level is a little low, but these are very small, and not many.

The tube is full of bubbles all in chaos, churning around madly.

It looks like this in real life.

The bubbles enter at the top just where the clear tube starts, and they move all the way to the bottom.

Which is also odd given how gently the water is flowing.





At first I thought they were the same bubbles, but if you block the holes, they clear after a few minutes.

Interesting.

As far as I can tell the air is dissolving.

I have no idea if I'm probably quite correct in thinking this.

If gas really does dissolve in water that readily and in that quantity, it's no wonder fish can live in the stuff.

I think I just got re-interested in the world.

Perhaps it's because I stopped taking all those opiates for my hurty ribs.



120 Things in twenty years  thinks ribs make me less thinky.


[EDIT FROM THE FUTURE - I Thought I'd add a link to wikipedia's entry on Venturi and now that I've read it I don't think I have any idea what I'm talking about, but what I did clearly works. I'm just no longer sure why]

The shell grit seed raising seems to have worked.

There was some slight discolouration on some leaves that I think might be due to nutrient lockout because the pH is probably off the chart in that local area, but generally speaking, I think it works. The discolouration is not shown well on this pic. The true colour is closer to the lettuce leaf on the left.



When pH is at certain levels, various elements become less available. If your system sits at about pH 7.0 then everything is available.

I just lifted my first seedling out of the shell grit, and it had a 24cm root that came out in tact. I made no attempt to be gentle and just lifted it out. I tried another one and achieved the same result.

Anyway, no washing - not even a rinse, and three tiny bits of shell grit was all there was stuck to the roots.

I think I should have left it a little longer because there were hardly any side roots developed, but I planted it next to some existing established kale, so I'll have something to compare it with. The existing kale was planted around ten days earlier.

I add some seasol® from time to time, so I might add it directly into the shell grit once I see sprouts to make sure there are extra trace elements available next time. The slight discolouration might also be due to lower oxygen levels as the water probably moves quite slowly through the fine particles. I might sive the shell grit so I can get a slightly bigger particle size. I plan on reusing it for ever, so it's no big deal to sieve it.



120 Things in 20 years thinks raising seedlings in shell grit feels like a success

Aquaponics - Duckweed

Since I moved my duckweed into it's new home it's growing like some kind of thing that grows a lot.

It looked like this nineteen days ago.

Then eighteen days ago I lost a lot of it because I overflowed my tank and all the duckweed went for a walk over the edge.

It looks like this today.

It's not lost on me that this is a poor comparison.

I realise they look pretty much the same, but this latest one is many layers thick in most parts. The original pic is all a single layer thick. I had no idea it could grow this way in multiple layers.





I suspect this is a dangerous thing to grow on top of a fishtank as it might choke the water. I doubt  the water will see enough oxygen. If not for the fact that I only have one fish, I think there could be trouble.

I think I might scoop all this out and do a time lapse of it growing back, but then I think I might move it into some other containers or something.


120 Things in 20 years wants some trout fingerlings.